20 vs. 25 for 14.5 Aluminum V

[WallyLooker]

I am replacing a 1986 Mercury 25 hp long shaft on a 14.5 foot aluminum v. The boat is about 500 lbs. dry and is rated for 40 hp. The present 25 has all the performance I need but I want the fuel efficiency, quiet operation and ease of starting of a 4 stroke. Plus I want to get electric start.

My dilemma is the extra weight of a 25 versus the 20. A new 4 stroke 20 will be in the same weight range as my present Mercury but all the 25's are around 60-70 lbs. heavier. I'm not only concerned about the extra weight on the boat but presently I can remove the motor to carry it in for service which I think will be unrealistic when I start getting into the 160 + lbs range.

I'm afraid if I get a 20 I will eventually be disappointed with performance.

I'd appreciate your opinions and thoughts.

 

[TOHATSU GURU]

Re: 20 vs. 25 for 14.5 Aluminum V

The 20 is a 2-cylinder carbed and the 25 is an EFI. Due to the weight difference your hole shot will be close with the same pitch prop. But, once you get on plane the EFI would give you around 6 to 8 mph more at top end.

Figure the boat at 1000 lbs loaded so somewhere around 24 to 26 with the 20 and 30 to 32 with the 25.

The 25 runs smoother and faster

The 20 is lighter, cheaper and will have the same hole shot.

Tohatsu designed the 20 to be used anywhere in the world with little or no technical support. The 25 is state of the art EFI and requires actual skill to troubleshoot and repair.

 

[BF]

Re: 20 vs. 25 for 14.5 Aluminum V

Last summer friends replaced their 2 stroke 20 or 25 (I don't remember) on aluminum boat with a 20 hp honda. They're disappointed with the drop in performance.

This spring I replaced my old 25 hp Evinrude, with a new 25 hp 4 stroke EFI merc (3 cyl, with dual rope/elec start)... it's on a 16' aluminum boat rated for a 35 hp. I'm happy with the performance of mine, it's a stronger torquier motor than my old 25 hp, and top speed has gone up a couple mph. But yes it's way heavier. With my old 25 I always kept a 6 hp kicker on the transom beside it, and used the 6 for trolling. I figure I'll only use the new motor now, and that its total weight is pretty close to the combined weight of my old 25 plus the 6 hp. So weight on the transom is the same.

Anyway, after my friends' experience, I opted to go with a 25 hp (3 cyl) engine rather than the 15/20 hp (2 cyl) size. Fuel economy of the new motor is great compared to my old one.

I'm still in break-in period, so I'm not sure yet how happy I will be trolling with my new motor compared to a small kicker. We'll see. You're right about them not being a portable. Mine is supposed to be through-bolted to the hull anyway, so I won't be removing it for the winter like I used to with my old one.

Performance-wise, I'm glad I didn't go any smaller. That's my $.02. Good luck.

 

[DRIFTER_016]

Re: 20 vs. 25 for 14.5 Aluminum V

At the lodge I have been guiding at for the last 15 years we went from 30 hp 2 strokes to 30 hp 4 strokes 5 or so years ago. Performance has suffered somewhat (40 hp would have been better) but overall they are a much better motor with fewer problems and much better mileage. I would opt for a 25 or 30 horse motor for your boat.

 

[WallyLooker]

Re: 20 vs. 25 for 14.5 Aluminum V

Thanks for the replies.

It looks as if a 20 HP would be sufficient but I'll be taking a chance on being disappointed with performance. I believe I'll go for the 25, move some weight forward in the boat and deal with the motor staying mounted.